'Gunny' is the popular nickname for a USMC Gunnery Sergeant, the 7th Enlisted Rank in the Marines. As a rank it is above a Staff Sergeant and below Master Sergeant.
Gunnery Sergeants typically serve in infantry units in command of anywhere between 23-69 Marines and are selected from Sergeants with superior intelligence and proven reliability.
Our K&C 'Gunny' is carrying a Thompson sub machine gun in addition to his M1911, Colt Automatic Pistol.